A bump on the back of the head has many possible causes, including injuries, cysts, fatty growths, inflamed hair follicles, and bone spurs. Bumps on this part of the body can be hard or soft, and they can vary in size.
Injuries are a common cause of bumps and lumps on the back of the head. As forceful blows to the head can lead to brain injury, it is important for a person to watch for symptoms of concussion. People with a concussion or another severe head injury should seek medical attention.
Some other causes of bumps on the back of the head may also require a person to contact a doctor.
This article explores some possible causes of a bump on the back of the head. It also explains when to speak with a doctor.
An injury is a common cause of a bump on the back of the head. Possible causes of head injuries include:
- falling backward
- impacts or collisions during contact sports
- hitting the head against the headrest of a car seat in a traffic accident
- other types of accident
A blow to the back of the head can cause a scalp hematoma, which is where a collection of blood just beneath the skin forms a semisolid bump. People sometimes refer to these bumps as “goose eggs.”
People can usually treat minor head injuries at home with rest, over-the-counter pain relievers, and ice packs.
However, more serious injuries can cause a concussion. A severe concussion can lead to dangerous complications if a person does not receive treatment.
The symptoms of concussion can
- nausea and vomiting
- problems with walking or balance
- a severe headache
- slurred or affected speech
- vision problems
- loss of consciousness
People with symptoms of concussion should seek immediate medical attention.
It is advisable for anyone who has hit their head very hard or been in a serious accident to go to the emergency room even if they do not yet have symptoms of concussion. A doctor can perform tests to rule out concussion and other brain injuries.
Pilar cysts are skin cysts that usually develop on a person’s scalp but can also occur on the neck. Doctors sometimes refer to pilar cysts as trichilemmal cysts.
These cysts are smooth, dense lumps containing a buildup of keratin, the protein the body uses to make hair and nails. Pilar cysts usually grow slowly, and they typically vary between
Pilar cysts are
Pilar cysts are
If a cyst is not causing symptoms, treatment may not be necessary. However, if a pilar cyst is leading to discomfort or other problems, a doctor may recommend surgically removing it.
A lipoma is a soft, fatty growth that can develop underneath the skin. Lipomas can occur anywhere on the body, including the back of the head and neck.
These bumps can vary in size, but they are not usually painful. A lipoma will typically feel soft and rubbery, and it may move around when a person presses down on it.
Doctors do not fully understand what causes lipomas, but they occur most often in people aged 40–60 years and are slightly more common in males than in females.
Lipomas are generally harmless and usually do not require treatment. However, if a lipoma becomes very large or is causing a person problems, a doctor may recommend surgical removal.
Doctors may also suggest removal if they are uncertain whether the bump is a lipoma.
A bone spur, also known as exostosis, is a bony outgrowth that can develop around a joint. Bone spurs most often grow in the:
- lower back
- foot or heel
- big toe
Bone spurs feel like hard, immovable lumps. Although they are not always tender, these growths may cause pain if they rub against or put pressure on bones, tissues, or nerves.
They can develop near the affected joints in people with osteoarthritis. Osteoarthritis causes degenerative changes in the cartilage and bone in the joints, where bone spurs form during the process.
Bone spurs do not usually require intensive treatment. If they are causing a person pain or other problems, a doctor may recommend:
- pain relievers
- maintaining a moderate weight
- physical therapy
In some cases, they may advise surgery to remove the bone spur.
Acne develops when the hair follicles become clogged with a buildup of skin cells and sebum, which is an oily, waxy substance. As the scalp consists of many hair follicles, acne can also develop on the scalp and around the hairline.
The American Academy of Dermatology Association notes that some hair care products can also cause scalp acne.
Although the acne can resolve without treatment, some people may require medicated products.
Scalp folliculitis is a condition in which hair follicles on the scalp become inflamed. The inflammation can cause a pus-filled bump that may resemble a pimple and can grow larger.
The symptoms of folliculitis can include:
- a white head on top of the bump
Infection may occur in the affected follicles.
At home, people can apply a warm compress to help reduce inflammation and drain the pus. They can also apply an antibiotic ointment and wash their hair with anti-dandruff shampoo.
A doctor may recommend oral antibiotics or prescription creams or ointments for people with more severe scalp folliculitis.
An ingrown hair occurs when a hair that is unable to grow out correctly grows back under the skin instead.
If hairs become ingrown, they can cause raised, inflamed, itchy spots on the skin. These may occur if a person shaves their head. They are more likely to occur in people with curly hair.
Most ingrown hairs will resolve without treatment, but a doctor may prescribe antibiotics if an infection develops. To minimize the risk of infection, people should avoid picking at the ingrown hair.
An epidermoid cyst is a benign cyst consisting of cheese-like keratin inside a distinct sac wall. These cysts are common and not cancerous.
Epidermoid cysts often have a visible punctum, which is a small central opening. They are the
A dermatologist may be able to remove the cyst. If they manage to remove it in whole, with the sac wall intact, it is unlikely to grow back.
In rare instances, a bump on the back of the head can be a bone tumor. One of the more common types of cervical spine tumors is a chordoma, which is a tumor that can grow from the bones at the base of the skull. However, in comparison with all bone cancer types, a chordoma is rare.
Small chordomas typically do not cause noticeable symptoms. However, the symptoms of larger chordomas may
- walking and balance difficulties
- hearing problems
- visual disturbances
It is possible for chordomas to spread to other parts of the body.
The treatment for a skull bone tumor will depend on multiple factors, including whether the tumor is benign or cancerous, the size of the tumor, the location of the tumor cells, and other individual variables.
It is important to contact a doctor if the bump on the back of the head:
- seems to be getting larger or is worsening
- is causing severe pain or other problems
- is producing pus or discharge
- is warm to the touch, or the surrounding area is discolored
People who have been in a serious accident or sustained a severe head injury should go to the emergency room.
It is also important to seek immediate medical attention if any of the following symptoms occur following a head injury:
- loss of consciousness, lethargy, or seizures
- persistent vomiting
- clear or bloody discharge coming from the ears or nose
- different sized pupils in the eyes
- slurred speech, confusion, or memory loss
- balance or walking difficulties
Injuries are a common cause of bumps on the back of the head. People can usually treat mild head injuries at home. However, people with severe head injuries or symptoms of concussion should seek immediate medical attention.
Other causes of bumps on the back of the head can include cysts, fatty growths, acne, inflamed hair follicles, epidermoid cysts, and bone spurs.
People should contact a doctor about any bump that is causing problems or seems to be getting larger or worse.